Nanoparticles of 4,7-dichloro-2-quinolinemethylacrylate-based copolymers and their potential cytotoxic activity on human breast carcinoma cells

ICTP

In this article, an improved synthesis strategy of the potent anticancer compound 4,7-dichloro-2-quinolinemethanol (QM) and its acrylate ester 4,7-dichloro-2-quinolinemethylacrylate (AQM) are described. AQM is copolymerized using free-radical polymerization with N-vinyl-2-pyrrolidone (VP) and the copolymers obtained from different molar ratios of monomers are subjected to nanoprecipitation to produce suspensions of nanoparticles (NPs) in phosphate buffered saline (PBS). The smallest and stable NPs are

prepared with the AQM-VP copolymers 45:55 and 40:60 (118.9 and 128.7 nm in diameter, respectively) at 1 mg mL−1, and along with AQM and QM, are evaluated for their cytotoxic activity on MDA-MB-453 breast carcinoma cells using MTT bioassay. AQM and QM are highly cytotoxic (IC50: 19 and 41 μM, respectively); however, the NPs are not cytotoxic in the range of the assayed concentrations. These results contribute to the search for new polymeric NPs with potential application as QM delivery systems for the treatment of cancer or other diseases treatable with QM.

 

1.
Valle, H. et al. Nanoparticles of 4,7-dichloro-2-quinolinemethylacrylate-based copolymers and their potential cytotoxic activity on human breast carcinoma cells. Journal of Applied Polymer Science 136, 47545 (2019). Cite

Enzymatically Cross-Linked Silk Fibroin-Based Hierarchical Scaffolds for Osteochondral Regeneration

ICTP

Osteochondral (OC) regeneration faces several limitations in orthopedic surgery, owing to the complexity of the OC tissue that simultaneously entails the restoration of articular cartilage and subchondral bone diseases.

In this study, novel biofunctional hierarchical scaffolds composed of a horseradish peroxidase (HRP)-cross-linked silk fibroin (SF) cartilage-like layer (HRP-SF layer) fully integrated into a HRP-SF/ZnSr-doped β-tricalcium phosphate (β-TCP) subchondral bone-like layer (HRP-SF/dTCP layer) were proposed as a promising strategy for OC tissue regeneration. For comparative purposes, a similar bilayered structure produced with no ion incorporation (HRP-SF/TCP layer) was used. A homogeneous porosity distribution was achieved throughout the scaffolds, as shown by micro-computed tomography analysis. The ion-doped bilayered scaffolds presented a wet compressive modulus (226.56 ± 60.34 kPa) and dynamic mechanical properties (ranging from 403.56 ± 111.62 to 593.56 ± 206.90 kPa) superior to that of the control bilayered scaffolds (189.18 ± 90.80 kPa and ranging from 262.72 ± 59.92 to 347.68 ± 93.37 kPa, respectively). Apatite crystal formation, after immersion in simulated body fluid (SBF), was observed in the subchondral bone-like layers for the scaffolds incorporating TCP powders. Human osteoblasts (hOBs) and human articular chondrocytes (hACs) were co-cultured onto the bilayered structures and monocultured in the respective cartilage and subchondral bone half of the partitioned scaffolds. Both cell types showed good adhesion and proliferation in the scaffold compartments, as well as adequate integration of the interface regions. Osteoblasts produced a mineralized extracellular matrix (ECM) in the subchondral bone-like layers, and chondrocytes showed GAG deposition. The gene expression profile was different in the distinct zones of the bilayered constructs, and the intermediate regions showed pre-hypertrophic chondrocyte gene expression, especially on the BdTCP constructs. Immunofluorescence analysis supported these observations. This study showed that the proposed bilayered scaffolds allowed a specific stimulation of the chondrogenic and osteogenic cells in the co-culture system together with the formation of an osteochondral-like tissue interface. Hence, the structural adaptability, suitable mechanical properties, and biological performance of the hierarchical scaffolds make these constructs a desired strategy for OC defect regeneration.

1.
Ribeiro, V. P. et al. Enzymatically Cross-Linked Silk Fibroin-Based Hierarchical Scaffolds for Osteochondral Regeneration. ACS Appl. Mater. Interfaces (2019) doi:10.1021/acsami.8b21259. Cite

 

α-Tocopheryl Succinate-Based Polymeric Nanoparticles for the Treatment of Head and Neck Squamous Cell Carcinoma

ICTP

The aim of this work is to study, in an in vitro head and neck squamous cell carcinomas model the anti-angiogenic and anti-migratory properties of self-assembled polymeric nanoparticles (NPs) with demonstrated selective anticancer activity. The NPs are based on α-tocopheryl succinate (α-TOS) encapsulated in the hydrophobic core of the NPs. We analyzed the effect of the newly synthetized α-TOS-loaded NPs in proliferating endothelial cells and hypopharynx carcinoma squamous cells and measured markers of angiogenesis, apoptosis and reactive oxygen species (ROS). α-TOS-loaded NPs suppressed angiogenesis by inducing accumulation of ROS and inducing apoptosis of proliferating endothelial cells. These NPs also decrease the number and quality of capillary-like tubes in an in vitro three-dimensional (3D) experiment, decrease the production of the pro-angiogenic vascular endothelial growth factor and down-regulate the expression of its receptor. The anti-migratory efficacy of α-TOS is corroborated in hypopharynx carcinoma cells by decreasing the secretion of matrix metalloproteases 2 and 9 (MMP-2 and MMP-9) and inhibiting cell migration. These results confirm that α-TOS-based NPs not only present anticancer properties, but also antiangiogenic properties, therefore making them promising candidates for multi-active combinatorial anticancer therapy.

Polymeric Nanoparticles for Cancer Therapy and Bioimaging

ICTP

Polymeric nanoparticles have demonstrated to be good candidates as vehicles of drugs or molecules for combined treatment and diagnosis of cancer. In comparison with inorganic nanoparticulated systems, they present remarkable benefits in terms of stability, biocompatibility, biodegradability, tailorability and low cost. Polymeric nanoparticles can be design to passively or actively accumulate in tumor sites by controlling their hydrodynamic properties or functionalizing their surface with targeting molecules. Moreover, polymers responding to particular tumor microenvironment conditions like reduced pH, high levels of reactive oxygen species or overexpressed enzymes, can be used to trigger a controlled drug delivery, a contrast agent exposure, or to enhance the therapeutic effect of a theranostic system.

This chapter focuses on the most recent advances in this field by discussing in depth examples of nanoparticles that, exploiting all these strategies, can be visualized with one or more imaging techniques: optical imaging, MRI, US, PA, PET, SPECT or CT; and present therapeutic effect (i.e. chemotherapy, gene therapy, photothermal or photodynamic therapy) due to the presence of active moieties.

In Situ Cross-Linkable Polymer Systems and Composites for Osteochondral Regeneration

ICTP

Injectable hydrogels have demonstrated being a promising strategy for cartilage and bone tissue engineering applications, owing to their minimal invasive injection procedure, easy incorporation of cells and bioactive molecules, improved contact with the surrounding tissues and ability to match defects with complex irregular shapes, characteristics of osteoarthritic pathology. These unique properties make them highly suitable bioscaffolds for treating defects which are otherwise not easily accessible without and invasive surgical procedure. In this book chapter it has been summarized the novel appropriate injectable hydrogels for cartilage and bone tissue engineering applications of the last few years, including the most commonly used materials for the preparation, both natural and synthetic, and their fabrication techniques. The design of a suitable injectable hydrogel with an adequate gelation time that gathers perfect bioactive, biocompatible, biodegradable and good mechanical properties for clinical repair of damaged cartilage and bone tissue is a challenge of significant medical interest that remain to be achieved.

Osteochondral angiogenesis and promoted vascularization: New therapeutic target

ICTP

The control of the different angiogenic process is an important point in osteochondral regeneration. Angiogenesis is a prerequisite for osteogenesis in vivo; insufficient neovascularization of bone constructs after scaffold implantation resulted in hypoxia and cellular necrosis. Otherwise, angiogenesis must be avoided in chondrogenesis; vascularization of the cartilage contributes to structural damage and pain. Finding a balance between these processes is important to design a successful treatment for osteochondral regeneration. This chapter shows the most important advances in the control of angiogenic process for the treatment of osteochondral diseases focused on the administration of pro- or anti-angiogenic factor and the design of the scaffold.

pH-sensitive polymeric nanoparticles with antioxidant and anti-inflammatory properties against cisplatin-induced hearing loss

ICTP

Polymeric nanoparticles (NP) based on smart synthetic amphiphilic copolymers are used to transport and controlled release dexamethasone in the inner ear to protect against the ototoxic effect of cisplatin. The NP were based on a mixture of two pseudo-block polymer drugs obtained by free radical polymerization: poly(VI-co-HEI) and poly(VP-co-MVE) or poly(VP-co-MTOS), being VI 1-vinylimidazole, VP N-vinylpyrrolidone, and IBU, MVE and MTOS the methacrylic derivatives of ibuprofen, α-tocopherol and α-tocopheryl succinate, respectively. The NP were obtained by nanoprecipitation with appropriate hydrodynamic properties, and isoelectric points that matched the pH of inflamed tissue. The NP were tested both in vitro (using HEI-OC1 cells) and in vivo (using a murine model) with good results. Although the concentration of dexamethasone administered in the nanoparticles is around two orders of magnitude lower that the conventional treatment for intratympanic administration, the NP protected from the cytotoxic effect of cisplatin when the combination of the appropriate properties in terms of size, zeta potential, encapsulation efficiency and isoelectric point were achieved. To the best of our knowledge this is the first time that pH sensitive NP are used to protect from cisplatin-induced hearing loss by intratympanic administration.

Multifunctional decoration of alpha-tocopheryl succinate-based NP for cancer treatment: effect of TPP and LTVSPWY peptide

ICTP

Active targeting not only of a specific cell but also a specific organelle maximizes the therapeutic activity minimizing adverse side effects in healthy tissues. The present work describes the synthesis, characterization, and in vitro biological activity of active targeting nanoparticles (NP) for cancer therapy based on α-tocopheryl succinate (α-TOS), a well-known mitocan, that selectively induces apoptosis of cancer cells and proliferating endothelial cells. Human epidermal growth factor receptor 2 (HER2) targeting peptide LTVSPWY (PEP) and triphenylphosphonium lipophilic cation (TPP) were conjugated to a previously optimized RAFT block copolymer that formed self-assembled NP of appropriate size for this application and low polydispersity by self-organized precipitation method. PEP and TPP were included in order to target not only HER2 positive cancer cells, but also the mitochondria of these cancer cells, respectively. The in vitro experiments demonstrated the faster incorporation of the active-targeting NP and the higher accumulation of TPP-bearing NP in the mitochondria of MDA-MB-453 HER2 positive cancer cells compared to non-decorated NP. Moreover, the encapsulation of additional α-TOS in the hydrophobic core of the NP was achieved with high efficiencies. The loaded NP presented higher cytotoxicity than unloaded NP but preserved their selectivity against cancer cells in a range of tested concentrations.

Contribution of bioactive hyaluronic acid and gelatin to regenerative medicine. Methodologies of gels preparation and advanced applications

ICTP

The functionality and reactivity of polysaccharides, and in particular hyaluronic acid, in combination with proteins like gelatin, collagen and many others, offer very interesting opportunities for the new trends in regenerative medicine. In this review is described the relevance of gelatin (Gel) and hyaluronic acid (HA) biopolymers in the field of tissue engineering due to the excellent response of these biomimetic materials and their bioactive and biodegradable character in the human body. In addition, it is reported an overview of the most relevant crosslinking processes and agents that are being developed for regenerative medicine, including different hydrogel modifications as well as several interesting and advanced applications. The growing of clinical applications of these macromolecular components as assemblies opens new and advanced opportunities in regenerative medicine and drug delivery fields.

Free download until 16.12.2017: https://authors.elsevier.com/c/1VyP~3GBFCik9

Biocompatible and bioadhesive low molecular weight polymers containing long-arm catechol-functionalized methacrylate

ICTP

Excellent adherence properties of blue mussels have been attributed to a catechol-containing amino acid, L-3,4-dihydroxyphenylalanine. This natural form of adhesion has been a source to develop bioadhesive polymers that adhere to biological interfaces. In this study, we describe a bioinspired approach for preparing bioadhesive and biocompatible materials based on synthetic low molecular weight copolymers of a flexible catechol-functionalized methacrylate (CEMA) and N-vinylcaprolactam. Copolymers with CEMA contents in the range 0.9–13.5 mol% were obtained by radical copolymerization. These systems show good biocompatibility and provide good antioxidant behavior and anti-inflammatory activity. Likewise, hydrogels prepared by mixture of a selected copolymer with gelatin possess good bone bioadhesive properties. These findings show that copolymer composition can be used as a tool for the preparation of biomedical systems with tunable properties and great potential for the development of drug delivery systems and bioactive gels that can be applied in tissue regeneration processes.

Free download until 29.12.2017: https://authors.elsevier.com/a/1W19k3GBFCkqt

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